Microsoft confirmed last year that it was merging the modern ("OneNote for Windows 10") and classic (Win32) OneNote applications on Windows into one combined application, and now the company has detailed its recent and upcoming changes.
The updated OneNote app has a similar layout as the classic OneNote app, but with a completely refreshed look and feel to match Windows 11 (and Microsoft's other modern apps). There's still a ribbon interface at the top with tabs for switching between tools, just like all the other Office applications. For anyone used to the simpler view in OneNote for Windows 11, there's a toggle to switch to a simplified ribbon with fewer buttons.
Microsoft has updated the look of the section tabs and notebook dropdown, and there are more rounded corners throughout the whole app. The window frame even has the same 'Mica' effect as some other modern Microsoft apps, where the color slightly changes depending on what is behind the window --- like a more subtle version of Aero on Windows Vista and 7.
Ink support (drawing) is one of the main features of OneNote, and the updated version still has all the usual writing and drawing tools. The tools are similar to what you get in Word, Excel, and PowerPoint, with an 'Ink to shape' tool for drawing cleaner lines and a ruler for drawing straight lines. There's also an 'Ink to text' feature that converts text to a font size similar to your original writing.
The updated OneNote also has a few tie-in features with drawing and voice dictation. The voice dictation feature was already in testing, but when transcription is on, OneNote will record your drawings in sync with the audio recording. When you're ready to review everything, the ink will play back in lockstep with the original recording. Voice dictation will also support phrases like "delete that."
Ink to shape, ink to text with font size awareness, and page sorting are all already rolled out in the Office OneNote app, and the options to insert a photo from camera and an improved share button are being tested in the Office Insider Program. Everything else (like some of the design changes and the pen focus view) is coming at some point in the future.
Eventually, the plan is for this updated OneNote app to replace 'OneNote for Windows 10,' which was a Universal Windows Platform (UWP) app. Microsoft stopped working on most UWP apps a few years ago, due to the failure of Windows Phone/Windows 10 Mobile and a lack of interest from other developers. As a result, Microsoft has been updating the original OneNote for Windows with a new interface and more features.
Source: Microsoft Tech Community